The invention relates to an ultra-wideband receiver for ultra-wide band radio transmission which uses discontinuous pulse signals as transmission signals.
In an analog front end circuit in an ultra-wideband receiver, an amplifier is a block which consumes an electric power most. Therefore, in order to reduce the power consumption in the receiver, it is effective to decrease the electric power consumed in the amplifier. In a narrowband radio transmission, a transmitted signal is in the form of a continuous wave because data is transmitted on a carrier wave. Therefore, a large current always flows through the amplifier in the receiver, and this makes the power consumption very large. On the contrary, in the ultra-wideband transmission, a carrier wave is not used, and the transmitted signals are made of discontinuous short pulses. (For example, refer to Jeongwoo Han and Cam Nguyen, A New Ultra-Wideband, Ultra-Short Monocycle Pulse Generator with Reduced Ringing, Microwave and Wireless Components Letters, Vol. 12, (2002) pp. 206-208 (IEEE); Hyunseok Kim, Dongwon Park and Youngjoong Joo, Design of CMOS Scholtz's Monocycle Pulse Generator, 2003 IEEE Conference on Ultra Wideband Systems and Technologies (UWBST 2003), pp. 81-85; Igor J. Immoreev, Alexander A. Sudakov, Ultra-Wideband Communication System with High Data Rate, 2002 IEEE International Workshop on The Ultra Wideband and Ultra Short Impulse Signals (UWBUSIS 2002); Robert Fleming, Cherie Kushner, Gary Roberts and Uday Nandiwada, Rapid Acquisition for Ultra-Wideband Localizers, 2002 IEEE Conference on Ultra Wideband Systems and Technologies (UWBST 2002) pp. 245-249; Joon-Yong Lee and Robert A. Scholtz, Ranging in a Dense Multipath Environment Using an UWB Radio Link, IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, Vol. 20, No. 9 (2002) pp. 1677-1683, and US-A 2002/0146080.)
In a prior art ultra-wideband receiver which uses discontinuous pulse signals for transmission signals, an amplifier amplifies a pair of receive pulse signal RFi and its counterpart/RFi, and a mixer multiplies the two signals with template signals generated by a template pulse generator. The template signals are used for determining the correlation with the received pulse signals. Previously, the template signals are discontinuous pulse signals similarly to the receive pulse signals.
As mentioned above, in a prior art ultra-wideband receiver which uses discontinuous short pulses for transmission, the amplifier consuming a large electric power is kept operated, and it consumes the electric power inefficiently. Therefore, it is desirable to reduce the consumption of electric power in the amplifier in the ultra-wideband receiver. Further, in order to generate template signals having the same waveforms as the input pulse signals, a complicated circuit including a pulse generator, a filter and the like is used, and this also enhances the power consumption in the receiver. Then, it is also desirable to reduce the consumption of electric power on this point.